Teleseismic detecting, signaling, and recording



Sept. 20, 1949. R. ARR-INGDALE TELESEISMI DETECTING,

SIGNALING, AND RECORDING 4 sheets-sheet 1 Filed March 28, 1946 NOM,

Sept. 20, 1949. R. L.. ARRINGDALE AND RECORDING v TELESEISMIC DETECTING, SIGNALING,

4 Sheets-Sheet 2 Filed March 28, 1946 dale. Lal/afi, d 6.

Iemam 4 shetslsheet s Sept. 20, 1949. R. 1 ARRINGDALE TELESEISMIC DETVECTING, SIGNALING, AND RECORDING Filed March 28, 1946 @s uw Y wv zu mw m E Q mv), www @n g W Illm ob flu/n .nh

Sept. 20, 19.49. R. L. ARRINGDALE 2,482,233

Y TELESEISMIC DETECTING, SIGNALING, AND RECORDING Filed March 28, 1946 4 SheetS-Shet 4 nanna-sept. zo, 1949 TELEEISMIG DETECTING, SGNALING,

- AND RECORDING new' L. Amarone, wakeaeld, Mass., assignml to Diamond instrument Company, Wakeeld, Mass., a. corporation oi Massachusetts Application March 28, 1946, Serial No. 657,698

(Cl. 17k-352) 6 Claims.

This invention relates to the detection, measurement and recording oi seismic disturbances and especially with respect to long-period shock waves and teleseisms. It aims to provide simple, efficient and otherwise improved apparatus and methods for the purpose and includes among its important objects the provision of a seismograph which is compact and of relatively light weight, s uch that it is readily manually portable for use in dierent locations.

In the drawings, illustrating by way of example `one embodiment of the invention, and whereby the methods thereof may be practiced:

Figs. 1 and 1A together illustrate somewhat schematically a ,portable long-period seismograph, the Fig. 1 portion of said illustration being in plan, and the Fig. 1A portion in elevation;

Fig. 2 shows in elevation one of the horizontal component elements, in this case that at the lower portion of Fig. 1, as it looking in the direction of larrow X placed below said iigure;

Fig'. 3 is an elevational view similar to Fig. 2 showing the vertical component element, as if looking in the direction of larrow Y of Fig. 1;

Fig. 3A is a horizontal sectional view through the column;

Fig. 4 is a fragmentary plan view of a portion of the record strip;

Figs. 5, 6 and "l are detail views upon a larger scale of certain levelling devices associated with the horizontal components of Figs. 1 and 2; and

Fig. 8 is a partly diagrammatic assembly view `upon a small scale of the several umts of a portable long-period seismograph embodying the invention.

, Referring rst to Figs. 1, 2 and 3,n these show one example of the initial "detecting and transducing unit of the seismograph of the invention, including a plurality of seismometer components responsive to a like number of different aspects of the earth-borne movements concerned, together with amplifying means for the signals deriving from each component. This initial unit comprises a platform I of general rectangular outline and equipped with levelling means shown as a plurality of supporting legs 2` threaded for vertically adjustable engagement with corner portions of the platform. The weight is predominantly at one main corner area, that at the lower rleft in Fig. 1, making it possible to avail of the adjusting ease and other advantages of a three-point support, the legs 2 being herein located at said main corner and at the two laterally adjacent corners.

Mounted in upright position at said main corner area or apex of support of the platform is a single column 3 which herein constitutes a common support for the plurality of seismometer elements to be described. Three such elements appear in Fig. 1. One of these is shown separately in Fig. 2 and another in Fig. 3. Each of them is herein suspended on and from the one column 3. These'seismometer elements are individually designated generally at A, B, and C in Figs. i to 3. Seismometers A and B, disposed along the mutually perpendicular side portions of the platform at which the legs 2 are located, are for detecting and metering two relatively perpendicular horizontal'components of the shock waves or telesesms. 'These horizontal components may be termed generally the longitudinal and the transverse components, with reference to the direction along the earth surface from the point of origin, or they may be identii'led by geographical directions. Seismometer A for example may be for the north-south component and seismometer B for the east-west component, or vice versa, de-

pending on the orientation of the apparatus. seismometer C, herein arranged in the angle between the other two and mounted on the same column 3 therewith, isjfor the vertical component of the particular teleseism. These elements are suspended operatively from the column in angular relation thereto and to each other in the same lateral or horizontal plane, which passes through the column near the base thereof.

The platform i with the seismometer elements A, B and C is adapted for use at any selected location, geographically speaking. At the particular station it is placed on a iirm earth-supported base such as an integral rock outcrop or a concrete block embedded in the ground, the platform being accurately levelled as by the means described. The platform may be a unitary plate of substantial strength and rigidity and in the'interest of portability may be of a light-weight material such as magnesium, aluminum or one of their alloys. Similarly the .supporting column 3 is a rigid upright member desirably of an integral structure adapted to maintain steady perpendicular relation to the platform, subject to the same earth-transmitted movements as the latter.

In the illustrated example the column 3 is of a generally rectangular and herein square crosssectional'form as seen in plan in Fig. 1, preferably with a slight upward taper from a solid base portion firmly anchored to the platform. An intermediate portion of the column may be longitudinally channeled, betweenvertical ribs 4 at 3 the column corners, Figa. 1 and 3A, making for lightness while retaining adequate rigidity. The columnas noted is set at a corner area of the platform I, with one corner diagonalof the column in substantial line with the 45 diagonal of the platform at that corner. At the inner medial corner, along the line of said diagonal, the column includes an integral or solidly joined vertical flange 5 at which the vertical component C of the apparatus is supported, as will be more fully described. While the column may be vari-y ously dimensioneddn a typical embodiment of the readily portable apparatus of thev invention the height above the platform level generally need not exceed about 18 to 24 in.

The plurality of component seismometer elements A, B and C present the relatively inert portions of the apparatus. Through the medium of the single column 3 they are herein all related in a common manner to the earth-supported portion, comprising mainly the platform these components A to C are commonly supported Y from the one column 3 of the earth-supported portion, the three directional components into which the vibrational effects are broken down are simultaneously detected with maximum accuracy and in their true relation as characteristics of the given teleseism. In other words the pluralityv of components A, B and C are at any one' instant all operatively referred to a single locusv on the earths surface.

' The two horizontal or longitudinal and transverse components A and C. forv descriptive convenience referred to as N-S and E-W, are similar in structure and arrangement and may in general duplicate each other in mutually perpendicular relation. A description of one of them accordingly will sufce for an understanding of the invention. To facilitate reference to Fig. 1 I have selected the E-W component B for separate illustration in Fig. 2, the latter an elevational view as if looking at the Fig. 1 apparatus in the direction oi the arrow thereon. Corresponding parts of the N-S component A have the same reference numerals on the drawing as for component B, with the addition ofv a prime mark.

Noting particularly Fig. 2 and referring also to Fig. l, the typical horizontal component of the invention comprises a beam 1 in the form of a cylindrical or other metallic rod having at its inner or supported end a conical fulcrum formation 8 centered in a jewel bearing 9. As will be more fully described with reference to Figs. 5 to 7 the beam 1 and its fulcral bearing means are herein provided with plural-directional sensitive adjusting mechanism.

The beam 1 is suspended by a truss-like frame comprising generally upright rods III and II. These converge upwardly in the vertical plane containing the beam axis and meet at an acute angle at their upper ends, where they are rigidly joined. One of the rods, herein the outer and more inclined rod I I, is extended beyond the juncture point. Near their lower ends the rods I and I I desirably are reinforced as by a strut I2 connected at one end to the rod I0 and at the other end to a straight terminal portion of the rod II. These rods I0 and I I terminate downwardly in 10 to a stud bearing collars I4, I5 respectively received on the beam 1 and adapted to be ilxed in different adjusted position along lt as by means'of set screws steel or comparable metal wire or other strand of relatively fine gauge but high tensile strength.

The described end-fulcrumed beam 1 with its truss I0, II and exible link I1 constitutes means for freely suspending upon the column 3 a calculated mass 20 such that the beam as a whole is afforded a marked inertia. This mass 20, shown as a block, is horizontally apertured substantially centrally lfor reception on the beam 1 with capacity for adjustment along it subject to securing asby a set screw or the like 2|. The mass 20 is set at such position along the beam, and the bearing 9 and attaching link I1 are so adjusted Y that the beam as a whole assumes a general horizontal position, substantially as in Fig. 2.

At the outer or free end of the beam 1 remote from its fulcrum 9 there is mounted a transducer means indicated generally at 25. In the partly diagrammatic example the transducer is shown as a coil 26 of extremely fine electrically conductive 5 wire, the coil being fixed coaxiallyat the end of earth-supported portion of the apparatuson the A in Fig. 1.

the beam'1. Disposed in inductive relation to the coil is a permanent bar magnet 21 adjustably held as by a set screw in a rigid supporting bracket 28 firmly anchored on the supporting platform I.

It will be understood that under the influence of teleseisms relative movement effective in the horizontal plane is set up as between the beam 1 and transducer 25, on the one hand, and the other hand; said earth-supported portion comprises the column 3, the platform I and particularly also in this connection the magnet 21 and the bracket 2li-rigidly connecting it to the platform. Such relative movement induces an electro-motive force in the transducer coll 26, this force of relatively low order being transmitted through suitable electrical connections to the E-W amplifier diagrammatically illustrated For example, one end of the transducer coil 26 may be grounded to the beam 1, the other end being connected by an insulated wire 29 Aextending along or through the beam 1 to the binding post 30B of a group thereof car- 60 ried by an insulating block 3| on the platform.

'I'he corresponding conductor 29 of the N-S component A connects to post 30A of the group.

The transducer 25 shown in the form of a relatively movableV coil and magnet may be of any known or preferred type including those avail'- ing of a variable reluctance, a variable capacity or of a piezo-electric function. Similarly the associated electric circuit feeding to the ampliner may be modified for operation with transducer means involving variation of inductance,

`resistance or capacity as well as one in which current is generated as in the example selected for illustratiom Considering still the horizontal components A and B of'Fig. 1 and the Fig. 2 showing of the ananas 5 E-W component B, the respective beams 1 and 1' desirably lhave damping means associated with them. For this purpose I have herein illustrated magnetic dampeners designated generally at 35 and 35'. These are represented as permanent magnets each comprising two legs 33, 31 and 36', 31' vertically disposed on bases 38, 33 ilxed on the platform I andpreferably adjustable relative to it in the direction lengthwise of the corresponding beam 1 or 1'. These beam-damping vmagnets 35, 35', which maybe other than of the permanent type, are set with the line of centers of their legsat right angles to the corresponding beam axis. The beams respectively extend through between the magnet legs, centrally thereof under normal inactive conditions,

and are thus subject tothe damping influence of the associated magnetic field.

Further in accordance .with the invention the horizontal components A and B are associated with the common supporting column 3 in such manner that the beam 1 or 1' of each component is subject t horizontal positional regulation in two directions, namely, lengthwise in the line of the beam axis and crosswise in the horlzontal direction perpendicular to the beam axis. As to each of the beams 1 and 1 the two bodily shifting adjustments may be accomplished each independentyvof the other. Means for this purpose is shown in detail in Figs. 5. 6 and 7 to which reference is now made, as well as to Fig. 1 and Fig. 2. The two-directional adjustment for each beam 1 and 1 is duplicated with respect to each of them, as will be apparent in Fig. 1. For the sake of clearness the adjusting means for but one of the means is shown in Figs. to '7, in this.

instance that for the E-W component B, the one shown separately in elevation in Fig. 2.

' Noting Figs. 5 and 6, the jewel bearing 9 for the fulcrumed end of the beam 1 is fixed at the end of a movable bar 40 extending through an enlarged transverse recess 4| in the column 3. This recess is horizontally dimensioned to permit the bar 4B to be bodily shifted transversely in parallelism with itself and in a horizontal direction at right angles to the vertical axis of the column 3, to an extent affording the desired range of adjustment in that direction for the bearing. The movable bar 40 'is slidably guided and supported at its end adjacent the bearing 9 in a cross-slide 42 having a dove-tailed or other undercut guide portion 43 received in a like-shaped way extending horizontally across the side face of the column 3 opposite the beam 1. The slide 42 is thus fixed i'elative to the column in the direction lengthwise of the beam but is guided for movement in the general horizontal plane perpendicular to the beam axis.

At the end of the cross-slide 42 remote from the bar 40 is a laterally projecting lnger 44 apertured for passage of a regulating screw 45. The latter is adjustably threaded into a tapped aperture for the purpose in the column'3, at the side wall thereof which faces the observer in Fig. 2. The regulating screw 45 has a thumb-wheel 46 at its outer end, beyond the projecting finger 44 of the cross-slide 42. A coil spring 41 surrounding the screw 45 and bearing between the finger 44 and the adjacent face of the column 3 urges the slide 42 together with the bar'40 and the beam vbearing 9 on the latter in the horizontal direction toward the observer in Fig. 2. Turning of the thumbwheel 46 in the direction to enter the screw 45 into the column 3 shifts the slide 42, bar 40 and bearing 9, consequently also the'beam 1 'as a whole, horizontally in said direction and against the spring. Similarly, opposite turning of the wheel 46 provides for opposite horizontal adjustment of the beam, under the influence of the spring 41. If preferred the screw 45 and the finger 44 of the slide 42 may be interconnected. as by an annular groove in the screw receiving the nger, for positive movement in both directions, ile spring then serving to avoid any play between For bodily adjusting the beam 1 in the direction lengthwise of its axis there is provided at the vertical face of the column 3 opposite the beam bearing 9 a threaded stud 50.4 'I'his extends in general parallelism with the beam and with the movable bar 4U. An integral or other plate-like .finger 5I on the adjacent end of the bar 49 has an elongated recess as at 52 for free passage oi the stud 50 and to allow for the previously described lateral adjustment of the bar 40. A Icoil spring 53 surrounds the stud 50 and bears between the finger 5I and the column 3 or an anchor nut 54 on the stud. Thus the finger 5l, the bar 40 and the beam bearing 9 thereon are urged in a horizontal direction to carry the bearing toward the column 3. An adjusting nut 55 is threaded onto the projecting portion of the stud 50 beyond the nger 5I, the nut having a rounded inner face for contact with the finger 5|. Turning oi the nut 55 in one or the other direction shifts the bar 40 longitudinally thereof and with it the beam bearing 9. Thus the beam as a whole is bodily adjusted in the axial direction, toward or away from the vertical axis of the supporting column 3.

As noted, 4the regulatory positioning of the given beam 1 or 1', in the two mutually perpendicular directions in the horizontal plane may be effected each independently of the other. Further, the thread formations of the transverse adjusting screws 45, 45 and of the longitudinal adjusting studs 50, 50' are of a pitch selected to g provide for precision setting by increments of any desired degree of in'eness. It will be apparent that the transverse adjustments, by the thumb- Wheels 46 and 46' bodily shift the corresponding beam with respect to the true vertical through its suspension point I8 or I3 at the top of the column 3. Similarly, the longitudinal or axial adjustments by the adjusting nuts 55 and 55 accomplish bodily adjustment of the seismometer beams relative to said true vertical but in a horizontal direction at right angles to the other adjustment. The two adjustments are intimately related and together regulate and control with extreme accuracy the amplitudes and the periods of relative horizontal deviation for the respective seismometer beams 1 and 1'.

Referring now to the element C, responsive to the vertical component of the earth-transmitted teleseisms, this element is seen in plan in Fig. 1 and separately in side elevation .in Fig. 3. As evident in Fig. 1 it is compactly disposed centrally of the two horizontal components A and B, substantially at the 45 angle between them. While in some instances the vertical component may be separately supported, in the preferred embodiment of the invention and as herein illustrated, it is mechanically related to the earth-supported portion of the apparatus by means of one and the same supporting column 3 from which the two horizontal components are suspended.

Accordingly the column 3 includes the vertically extending angev 5 previously mentioned, pro- Jecting at that corner portion of the column which is enclosed between the horizontal components A and B. Near the base of the column 3 the ange 5 has integrally or otherwise affixed atransverse block 60 on which is releasably secured as by screws or the like a clamping strap 6|. The parts 60 and 6I together provide a fulcrum and pivotal support for the vertical component C as a whole. The main beamV of this element is indicated generally at 65. It herein comprises a pair of horizontally spaced rods 66, 66 having their outer ends secured to a crosspiece 61. The two rods 66, 66' are rigidly interconnected at their inner ends by a. horizontally divided two-part strap or clamp 68 and at an intermediate point by a similar cross-member 69 the underpartof the latter having an integral dependent L-shaped foot or bracket 10, Fig. 3. The upper and lower sections of these cross-connections 68 and 69 are releasibly interconnected as by screws or the like affording capacity for adjustment of the relative spacing of the rods 66, 66' which together comprise the major part of the beam 65.

This beam 65 of the vertical component C is flexibly connected at its inner end to the bearer block 6 0, 6| in a manner providing for relative movement in the vertical plane as between the beam 65 and the earth-supported portion of the apparatus under the influence of the teleseisms. The flexible pivotal connection as herein shown comprises a plurality of relatively thin horizontally disposed strips 1I, 1I of metal or other material of a non-frangible character. These flexible strips 1I together with the block and strap members 60, 6| form fulcral supporting connec- 'tion as between the beam 65 and the column 3, through the flange 5 thereof. Accordingly the earth-supported column 3 and platform I have capacity for vertical movement relative to the beam 65, under the influence of the teleseisms.

The described beam 65 of the vertical component C includes means whereby it is made relatively inert in the absolute sense, that is, with reference to the surrounding space. For this purpose I have shown in Figs. l and 3 a composite mass including a main portion or block 15 and a secondary or auxiliary mass 16. These two masses may be solid or other blocks of substantial density and of a weight calculated and proportioned with respect to the length of the beam 65. They preferably are slidably mounted on the beam members 66 and 66 and secured in selected position of adjustment along them as by set screws 11, 18.

Suspension of the beam 65 with maximum independence in the vertical plane is afforded herein by means of an elongated vertical coil spring 80 having its lower end secured to the horizontal portion of the dependent Afoot 10 on the members 66 and 66 of the beam. At its upper end the spring 80 is fixedly connected to the lower en d of a threaded stud 8| vertically held in the outer end of a horizontal arm 5a rigidly extending from the upper partof the vertical flange 5 of the column 3. An adjusting nut 82 on the stud 8|` above the supporting arm 5a, whereby the stud and spring may be raised or lowered, provides for regulating the beam position in the vertical plane. It is noted that the spring 80 is of substantial length and has suspending attachment to the beam 65 below the center of mass, thus making for maximum freedom and stability for the beam 65. The spring not only affords support against gravity for the steady mass lcom- IG grounded on the platform I.

`furnishes restoring force, aided or opposed by gravity, in the event of displacement of the mass.

The beam 66 of the vertical component C, referring again to Figs. 1 and 3, includes at the outer end a terminal portion or rod 83 extending centrally from and beyond thecross-piece 61, in line with the'longitudinal axis of the beam 65 as a whole. Transducer means for this beam is provided, of any preferred type as already described in connection with seismometer elements A and B. In Figs. l and 3 the transducer is indicated generally at 86. It is represented similarly as for the horizontal components and herein includes a coll 86 coaxially mounted at the outer end of the beam extension 83 in spaced opposition to a permanent magnet 81 on a supporting bracket 88 on the platform I. As for the other components, one end of the coil is grounded, the other end being connected by a conductor 89 to the binding post 30C of the set of three thereof on the insulating block 3|, Figs. 1 and 2.

Likewise the vertical component C is equipped with dampener means, in this instance effective primarily in the vertical plane. Such means indicated generally at 96 in Figs. 1 and 3 may be generally similar as for the horizontal components but with the permanent or other magnet members 96, 91 horizontally disposed on a supporting base 98 on the platform- I. A plate 83a of armature material secured to the end rod 83 of the beam 65 stands vertically in the magnetic iiux path between the poles of the magnet members 96, 91, similarly as corresponding horizontal armature members for the4 beams 1 and 1.

From the foregoing it is evident that'individual electric signals conformant to the diierent components of the influencing teleseisms are available from each of the seismometers A, B and C by means of the respective transducer circuits. Each such circuit includes a coil-connected c onductor 29', 29 or 89 extending to the corresponding binding posts 30A, 30B or'30C of the group on the insulation 3|. The other side of each transducer coil, being grounded to its supporting beam 1, 1' or 65 and hence to the platform I, is accessible at one ofthe set of three binding posts IG, Figs. 1 and 2, in electrical contact with the platform I as indicated by the dotted rectangle and grounding symbol on Fig. 1.

The signals originating in the transducer circuits being of a relatively low order of power are fed to suitable amplifier means as diagrammatically indicated at I 00A, |00B and IO0C in Fig. 1 for the N-S, E-W and the vertical components A, B and C respectively. These if desired may be permanently assembled either with the Fig. 1 seismometer section of the apparatus or with the recorder section shown in Fig. 1A. For ease in handling it is found convenient to furnish the amplifier means as an individually portable unit |00X; see also Fig. 8.

The seismometer section is electrically connected to the amplification unit |00X by appropriate wiring which may be contained in a cable with plug-in or like detachable connections at either or both ends. The wiring includes for each of the seismometer circuits a pair of leads extending to the corresponding amplifier |00A, |00B or IO0C. One lead of each pair runs from one of the insulated binding Iposts 30A, 30B or 30C and the other from one of the set of posts On Fig. 1 .the lead pairs are designated respectively :at |0I, |02 for the N-S ampliiier IO0A, at |03, |04 for the 9i e E-W amplier IOB and at |05, |00 forltliev vertical ampliiler |000.

the provision of a seismograph record or seismogram on which the individual-record tracks for each of the plurality of seismometer components volving platen or drum 205 rotatably carried on the frame as at 200. 'I'he tape T is advanced to and past the recording station at the platen 205 by rotary feed means including a feed Wheel or drum 201 on a driven shaft 208 and having a cooperating follower roll 209 between which and the driven wheel 201 the tape .passes in feeding relation. The follower 209 has pressing contact with one face of the tape opposite the feed wheel 201, being yieldably and rotatably mounted on one or more arms 2|0 pivoted on the frame as at 2| i v The tape T carrying the plural-component seismographic record is continuously delivered from the recorder unit as at the lower right in Fig. 1A where it may be rewound or otherwise collected as by being accumulated into a basket or other receiver. The feed means 201 is adapted to be continuously driven at a :predetermined constant rate 'as by means of a small electric An important aspect of the invention lies in motor ZIB. This may be of the synchronous type such as used in electric clocks, energy being tsupplied from any available power source as through a plug-in connection Y2 i0.

'I'he several marking or recording instruments are each designated generally in Fig. 1A at 220A, 220B and 220C respectively. 'They lare in the nature oi' `galvanotneter-operated marking or inking devices. Each comprises a. marker, stylus or pen 22|A, 2MB, 22|C of any preferred selfsuppiylne, continuous marking or fountain type. To simplify the description the component parts of Ibut one 0f salvanometer-controlled markers will be described and numbered, that are made simultaneously and in visually juxta- 15 at the right in Fig. 1Anamely the marking eleposed position on a single recording medium. ment 220B, for the E-W component B. It will Further, the record vehicle is of relatively inexbe understood that the corresponding parts of s pensive and easily available material, as comthe other units 220A and 220C may be the same. pared with photographic or sensitized iilink here- This inking or other marking inetrwnent 22|B tofore in use, and is such that the recorder may be. is carried at the free end of an elongated marker furnished with a supply adequate for continuous erm 225 projecting radially from e coil 226- The recording over relatively long periods, such as coil iS mounted to Swing about a dlametrel axis several days or even a week or more, before reperpendicular to the marker arm 225, on e' S111)- plenishment is required. The associated reporting cross-shaft 220 having anti-friction bearcorder mechanism likewise is adapted forwcon- 25 ings on a nxed peri? .0f the unit. At the side tinuous automatic operation without attention of coll 22| opposite .the marking drm 225 end from an operator. Moreover, the transcription of in alignment With Ithe latter is an arm extension record may be had directly al, the detecting loca- 229 carrying an ediustment counter-balance 230., tion where the seismometer and amplifying units The typical marking unit .further comprises a of the apparatus are set up or at any convenient carrying base 0r bracket 232 Supported il!y any more or less remote point, through wired or other convenient ine-nner on ol edlecenil the recorder elect-,mm1 transmission housing 20| to present the marker unit in opera- In the preferredv form -and as herein repretive relation ilo the rote-ry Platen 205 and the sented the record-receiving medium is o, conrecord tapeTpa-Ssing over it.` The gal-vanometer tinuous strip or tape T of paper or other fibrous base 202 has fixed on it a Permanent or other eld or paper-like material, such as an' inexpensive magnet 233. illustrated e8 of U-Shepe and having grade of paper -as used in telegraphic tickers and Dole pieces 232. 235 et diemetrally Opposite Sides other business machjne5 This paper record tape 0f the COl 226 l'tatably Suspended between them. T may be relatively narrow,generally not more Under the lnuence ofthe electrical signals from than about 3 to 6 inches or thereabouts, depend- 40 the corresponding emplier, in this particular ing on the number and lateral spacing of the oase the amplier Icon of Fis. 1, the coil Swings plurality of seperate side-by-side tracks such es in one or the opposite direction about the exis of represented ou Fig, 4, its supporting shaft 220 and oscillates the mark- The recording unit as illustrated in Figs, 1A inginstrument 22|B in the direction transversely and 8 comprises a supporting frame or housing 45 of the record tape T, that is. toward and from the l20| on which the several elements of the record- Viewer looking et 1A. By reason of the ing means are compactly assembled. These inmechanical advantage of the elongated marker clude mechanism for supporting and continuouserm 225 relatively minute swinging motions of 1y advancing the record tape T past individual the coil are mcsnied in the resulting record recording instrumentaiities responsive to the track Such es represented on Fis. 4. correspondingiseismometer components A, B and While in illhe ,illustrated exemple the merkel' C. The recording tape desirably is supplied in means iS represented7 as a galvanometer-like the form of Va roll 202 rotatably supported on the device it will Abe understood that the electroframe as at 203, From the m11 supply 202 the mechanical translation vof the amplified signals tape T passes in supporting contact about; a resuperinduced by the transducer may be effected by any preferred means, including for example reversible electric motors operatively connected to the axes of the marker armsl and receiving the signals transmitted from the amplifier.

Each of the marker units 220A, 220B and 220C of whatever form is adapted for electrical connection with the corresponding .amplifier unit so as to receive the ampliiier seismometer signals transmitted from it. The connections, which may be by means of a multi-conductor cable with plug-in connection, include for each marker unit a set of three leads designated generally at 240A, 200B, 240C, Figs. 1 and 1A. Each such set of three leads comprises acommon wire a, a wire b providing therewith a circuit for the amplied seismometer signals and a wire c forming with the common line a a circuit for impulses from a timer. The timing impulses may be imposed directly at the recorder but for convenience in organization of the apparatus as a whole and consistent 1 l with the desired portability they are fed into and through the respective amplifiers IOA, I 00B and- I 00C. The timer may be located with any section `of the apparatus but desirably and as' illustrated and there having parallel connection with each Aof the individual amplifier sections IO0A, IO0B and IO0C. From the amplifier IO0X these timeindicating signals are transmitted in amplified form to the respective galvanometer 220A, 220B and 220C through the circuits comprised by the leads a and c of the triple series 240A, 240B and 240C already described.

In the enlarged fragmentary plan view of Fig. 4 there is shown a short length of the paper record tape T as it travels at a constant rate beneath the marking instruments or pens 22IA, 22IB and 22|C in the direction of the arrow at the bottom of Fig. 4. There the individual record tracks as transcribed in response to the signals from the three seismometer elements A, B and CI are indicated at 330A, 330B and 330C. In each of the tracks the time-indicating jogs formed in response to the operation of the timer means are indicated at i. Noting the right-hand portion of Fig. 4, it will be seen that the same instant in time is simultaneously indicated for each of the record tracks, the time logs i for each of them being directly in alignment transversely of the tape T and the several tracks are in such proxmity that a comparative visual reading of any and all of them, for any instant in time, is readily had. The respective record tracks are individually identied by their characteristic location upon the paper record. Merely by way of example the vertical component is herein shown as applying its track substantially centrally along the tape as at 330C, with the tracks for the two horizontal components closely spaced at either side of the vertical track. In the illustrative example the N-S component has its track below as at 330A and the E-W component above the central track as at 330B. Preferably the tracks are also visually diierentiated as by diierent colors of the ink or other marking medium, for example the three tracks reading from top to bottom in Fig. 4 may be green, red and black or whatever distinctive color may be preferred for the particular directional component. V

In Fig. 8 my portable long-period seismograph such as described in connection with the preceding figures is represented on a `reduced scale in its condition as readied for carrying, except that the plug-in cable connections between the respective units or sections of the apparatus generally will be disengaged for transport. The seismometer unit A-B-C is furnished with a removable covering container 40| equipped with convenient handle means. Similarly the amplifier section or unit IMX has a carrying container 402, while the recorder 'unit 200 including the tape record supply, the translating elements or pens and the timer, is likewise portably housed in a cover or container 403.

Any suitable form of housing carriers for the .I seismograph units may be employed. In the example of Fig. 8 thecases 410|', 02 and 403 are represented as of transparent plastic material shaped and proportioned to accommodate the respective units. The amplifier unit IO0X desir ably is arranged for operation either from a builtin battery power source or from an outside power source when such is readily available at the selected geographic location, a power inlet connection being indicated at IIO in Fig. 8. This alternative self-contained and plug-in power arrangement desirably also is provided for the recorder unit 200, the electric energy for which may be supplied from the same power-pack which serves the amplifier unit IO0X while the plug-in connection for an outside power line is indicated at 2I6,

Figs. 1A and 8. The connecting cable between the amplier and the recorder units IO0X and 200, the cable designated by the arrow and associated wiring numerals 240A-B-C and 302 in Fig. 8, may also carry the connecting leads for the power supply, whether the latter is from a self-contained or an outside source.

While in the drawings I have shown but one recording unit or station, it will be understood that by reason of the power amplication of the low-power signals derived from the set of seismometer elements, one and the same set of the latter may be employed to operate any desired plurality of recorders located either at the same or diierent stations including one or more stations more or less remote from thedetecting and transmitting locationj also that the transmission may be via wired or radio transmitting means.

From the foregoing it is evident that my disclosed invention novelly vprovides a compact and relatively inexpensive yet highly efficient manually portable plural-component seismograph capable of detecting and recording teleseisms. The apparatus is adapted for hand carrying to any selected place of operation. As there set up it functions automatically and with a minimum of attention, so that over continuous periods of a week or more it need be visited only when it is desired to examine the record. The medium on which the record is transcribed, being a paper or like inexpensive flexible tape, makes lfor marked economy in operation. Since the rate of tape travel at the recorder may be relatively slow, generally in the order of about 30 mm. per minute, a supply of the tape for a continuous 24- hour operation (approx. 140 ft. at the rate noted) costs but a few cents even at current prices in contrast with a cost of many times 'that amount for a photographic or sensitized strip record.

Moreover, the ink-marked paper tape record is ,immediately available at any instant forv examination and study and may at all times be exposed to the normal light. Thus any necessity for operation of the seismograph in a dark room is avoided and the record may be viewed without having first to remove and develop or print it.

.'Renewals of the record supply are called for i amazes trasts with the previous practice in which a number of separate records for two or more components required separate preparatory treatment and assembly before a comparative study of the different components could be made.

In addition to these and numerous other advantages which will be apparent from the foregoing description in connection with the drawings, the seismometer section of the apparatus novelly combines a plurality of detecting and transducing components upon a single supporting column, yet with full capacity for individual and 'relative plural-directional adjustment. While in some instances one of the components, as for example the vertical component, may be separately supported, preferably at least two of the components, generally the horizontal components including the longitudinal or N-S and the transverse or E-W, are thus commonly suspended on the single column while in the illustrated example all three components are afforded the common support, thus promoting faithful reproduction of the earth-borne vibrations as well as making for compactness and portability of the apparatus as a whole. It is here again emphasized that my apparatus is particularly adapted for long-period or teleseismic detecting and recording as contrasted with devices primarily designed and useful for only relatively short-period manmade or other vibrations such for example as those characteristic of prospecting operations.

' My invention is not limited to the particular embodiments thereof illustrated and described herein by way of example, and I set forth its scope in my following claims.

I claim:

1. A plural-component manually portable teleseismic detecting, signalling and recording system including a single supporting column and a plurality of seismometer elements for a like number of different components, said elements being operatively suspended from said column in angular relation thereto and to each other in the same horizontal plane, which passes through the column near the base thereof.

2. A manually portable long-period teleseismic detecting, signalling and recording system adapted to record teleseisms, comprising a platform carrying an upright column and seismometer elements for mutually perpendicular horizontal components, said horizontal component elements suspended from and attached to the column as the common support therefor positioned on a common horizontal plane and in spaced angular relation to the column and to each other.

3. A plural component manually portable teleseismic detecting, signalling `and recording system comprising upright supporting column means and a plurality of seismometer elements for a like number of different components, including two horizontal components and a vertical component, at least the two horizontal components being suspendedfrom and attached to one and the same upright element of the column means in spaced angular relation thereto and to each other.

4. In seismographic apparatus, a seismometer column, a plurality of generally horizontal beams freely suspended on and by the column in teleseism-detecting relation thereto and at an angle to each other, and means for independently adjusting -the vertical position of the beams relative to each other.

5. In seismographic apparatus, a seismometer column, a plurality of generally horizontal beams freely suspended on and by the column in teleseism-detecting relation thereto and at an angle to each other and means for independently adjusting at least one of the beams either and both A transversely and longitudinally.

6. Seismograph apparatus comprising, in combination, a seismometer assembly including a base, a single column on and rigid with the base, seismometer elements operatively suspended on the column'in angular relation thereto and to each other in the same horizontal plane, which extends through the column near its base for respectively detectinglongitudinal, transverse and vertical teleseismic components, each element having a transducer for effecting electrical variations signalling relative movement of the column and the particular element, amplifier means in circuit with the transducers to receive and amplify the respective signals therefrom, recording means presenting a continuously movable record strip, a marker device for each seismometer element adapted to trace upon the record strip, and electrical actuating means for each marker. device adapted to receive the amplified signals from the seismometer elements and to translate them into mechanical movement of the corresponding marker devices.

ROGER L. ARRINGDALE.

REFERENCES CITED The following-references are of record in the ille of this patent:

. UNITED STATES PATENTS Number OTHER REFERENCES Engineering, April is, 1923, pp. 474-477. Bulletin of the Seismological Society of America, oct. 1939, pp. S50-55s. 

